Imidazolinyl benzamides as herbicidal agents

ABSTRACT

The invention relates to imidiazolinyl benzamides and a method for the preparation thereof. The invention also relates to a method for the control of undesirable plant species by the application of a herbicidally effective amount of an imidazolinyl benzamide to the foliage of the undesirable plants or to soil containing seeds or other propagating organs of the plants.

DESCRIPTION OF THE INVENTION

The invention relates to imidazolinyl benzamides having the structure:##STR1## wherein R₁ is alkyl C₁ -C₄ ; R₂ is alkyl C₁ -C₆, cycloalkyl C₃-C₆, alkenyl C₂ -C₄, phenyl, halophenyl or benzyl; and when R₁ and R₂are taken together with the carbon to which they are attached they mayform cycloalkyl C₃ -C₆ optionally substituted with methyl; R₃ and R₄each individually represent hydrogen, alkyl C₁ -C₄, alkenyl C₃ -C₅,alkynyl C₃ -C₅, or benzyl; and when R₁ and R₂ represent differentsubstituents, the optical isomers thereof.

While the imidazolinyl benzamides of this invention are illustrated bythe structure identified as formula (I) above, it should be understoodthat these compounds may be tautomeric. As such, they could have thestructure: ##STR2## wherein R₁, R₂, R₃ and R₄ are as described. Bothtautomeric forms are, of course, intended to be included as compounds ofthe invention when reference is made throughout the specification andclaims to the formula I structure.

In accordance with the invention, imidazolinyl benzamides having thestructure: ##STR3## wherein R₁, R₂, R₃ and R₄ are as described above,can be prepared by reacting an imidazoisoindoledione having thestructure: ##STR4## where R₁ and R₂ are as described above, with anamine represented by the formula: R₄ R₃ NH (III) where R₃ and R₄ are asdescribed above.

The mole ratio of amine (III) to imidazoisoindoledione (II) should be inthe range of 1:1 to 10:1, and preferably 2:1 to 5:1. The reaction ispreferably conducted in a non-protic solvent such as tetrahydrofuran,dioxane, toluene, xylene, benzene, or the like, at a temperature between50° C. and 100° C.

It should also be understood that when R₁ and R₂ represent differentsubstituents, the carbon to which R₁ and R₂ are attached is anasymmetric center and the products (as well as their intermediates)exist in d- and l- forms as well as dl- forms. Further, when theimidazoisoindoledione (II) is optically active and either the d- or l-isomer is reacted with the formula (III) amine, R₄ R₃ NH, thecorresponding d- or l-imidazolinyl benzamide (I) is formed.

The intermediate imidazoisoindoledione (II), which are essential to thepreparation of the formula (I) imidazolinyl benzamides of the presentinvention, are described with a method for their preparation in my U.S.Pat. No. 4,017,510 (1977).

The method for the preparation of the compounds of the invention may begraphically illustrated as follows: ##STR5## wherein R₁, R₂, R₃ and R₄are as described above.

Illustrative of the compounds of this invention are:

o-(5-isopropyl-5-methyl-4-oxo-2-imidazolin-2-yl)-3-butynylbenzamide;

o-(5,5-diethyl-4-oxo-2-imidazolin-2-yl)-N,N-diethylbenzamide;

o-(5-isopropyl-5-methyl-4-oxo-2-imidazolin-2-yl)-N-2-butenylbenzamide;

o-(5-isopropyl-5-methyl-4-oxo-2-imidazolin-2-yl)-N-methylbenzamide;

o-(5-isopropyl-5-methyl-4-oxo-2-imidazolin-2-yl)-N-isopropylbenzamide;

o-(5-isopropyl-5-methyl-4-oxo-2-imidazolin-2-yl)-N-allylbenzamide;

o-(5-isopropyl-5-methyl-4-oxo-2-imidazolin-2-yl)-N,N-diallylbenzamide;

o-(5-isopropyl-5-methyl-4-oxo-2-imidazolin-2-yl)-N-1,1-dimethyl-2-propynylbenzamide;

o-(5-n-propyl-5-methyl-4-oxo-2-imidazolin-2-yl)-N-1,1-dimethylallylbenzamide;

o-(5-isopropyl-5-methyl-4-oxo-2-imidazolin-2-yl)-N,N-diphenylbenzamide;

o-(5-cyclohexyl-5-methyl-4-oxo-2-imidazolin-2-yl)-N-2-propynylbenzamide;

o-(5-benzyl-5-methyl-4-oxo-2-imidazolin-2-yl)-N,N-diisopropylbenzamide;

o-(5-isopropyl-5-methyl-4-oxo-2-imidazolin-2-yl)-N-benzylbenzamide; and

o-(4-oxo-1,3-diazospiro[4,5]dec-2-en-2-yl)-N-n-propylbenzamide.

Preferred compounds of the invention have the structure of formula Iabove, wherein R₁ is methyl; R₂ is alkyl C₁ -C₃, preferably isopropyl,cyclohexyl or benzyl, or when R₁ and R₂ are taken together with thecarbon to which they are attached they may represent cyclohexyl; R₃ andR₄ each individually represent hydrogen, alkyl C₁ -C₃, allyl,dimethylallyl, propynyl, or benzyl; and when R₁ and R₂ are different,the optical isomers thereof.

The compounds of this invention, as represented by formula I above, areuseful as herbicidal agents. They are effective for the control ofundesirable broadleaf weeds (dicotyledonous plants), sedges and grassplants (monocotyledonous plants), and may be used effectively for thecontrol of such plants by application thereof to the foliage of theplants or to soil containing seeds or other propagating organs of theplants.

Postemergence control of undesirable plants, particularly broadleafplants such as mustard, pigweed and morningglory, can be achieved byapplying a herbicidally effective amount of the formula I imidazolinylbenzamide to the foliage of the plants, preferably as a dilute liquidspray.

In practice, generally about 0.28 to 11.2 kg per hectare of the formulaI imidazolinyl benzamide will provide postemergence control of theabove-identified plants.

Preemergence control of both broadleaf weeds such as mustard, pigweed,morningglory, teaweed and velvetleaf; purple nutsedge, and grass plantssuch as barnyardgrass, crabgrass and green foxtail, is obtained when theformula I imidazolinyl benzamide is applied in a herbicidally effectiveamount, preferably also as a dilute liquid spray or as a granularformulation, to soil containing seeds or nutlets of the undesirableplants. Generally about 0.28 kg to 11.2 kg per hectare, and preferably1.12 kg to 11.2 kg per hectare, will provide the desired control.

Inasmuch as the compounds of this invention are relatively insoluble inwater and other common organic solvents, it is generally mostadvantageous to prepare the formula I imidazolinyl benzamides either asgranular formulations or as wettable powders or flowable liquids. Theselatter formulations are then dispersed in water or other inexpensiveorganic solvent for application as liquid sprays.

Wettable powders can be prepared by grinding together about 20% to 45%by weight of a finely divided carrier such as attapulgite, bentonite,kaolin, diatomaceous earth, or the like, 45% to 80% by weight of theimidazolinyl benzamide, 2% to 5% by weight of a dispersing agent such asthe sodium salt of condensed naphthalene sulfonic acids, sodiumlignosulfonate, or the like, and 2% to 5% by weight of a surfactant suchas sodium N-methyl-N-oleoyl taurate, alkyl phenoxy polyoxyethyleneethanol, or the like.

A typical flowable liquid can be prepared by admixing about 40% byweight of the formula I benzamide with about 2% by weight of gellingclay, 1% by weight of polyethylene glycol, 3% by weight of the sodiumsalt of condensed naphthalene sulfonic acids, and 54% by weight ofwater.

A typical granular formulation can be prepared by dissolving ordispersing the active ingredient in solvent and applying the solution ordispersion to a sorptive or non-sorptive carrier in sufficient amount toprovide 10% to 15% by weight of toxicant on the granular carrier.

The invention in the present application is further demonstrated by theexamples set forth below.

EXAMPLE 1 Preparation ofo-(5-Isopropyl-5-methyl-4-oxo-2-imidazolin-2-yl)-N,N-dimethylbenzamide

To a cold solution of 180 g of3-isopropyl-3-methyl-5H-imidazo[2,1-a]isoindole-2(3H),5-dione in 300 mlof dry tetrahydrofuran in a pressure bottle is added 68 g ofdimethylamine. The bottle is sealed and the mixture heated to 50° C.with stirring for 16 hours. The mixture is cooled, and the contents ofthe bottle transferred to a flask. The solvent is then removed in vacuo.The crystalline residue is then suspended in ether, filtered, washedwith ether, and air-dried to give 195 g ofo-(5-isopropyl-5-methyl-4-oxo-2-imidazolin-2-yl)-N,N-dimethylbenzamide,melting point 144°-146° C. This product is recrystallized fromacetonitrile to give an analytically pure product, melting point147°-150° C.

EXAMPLE 2 Preparation of Formula I Imidazolinyl benzamides

Using essentially the same procedure as that described in Example 1, butsubstituting the appropriate imidazo[2,1-a]isoindole-2(3H),5-dione andthe appropriate amine for dimethylamine, yields the compounds set forthbelow.

    ______________________________________                                         ##STR6##                                                                                                        Melting                                                                       Point                                      R.sub.1                                                                             R.sub.2    R.sub.3 R.sub.4   ° C                                 ______________________________________                                        (CH.sub.2).sub.5                                                                           H       H           211-212                                      CH.sub.3                                                                            CH(CH.sub.3).sub.2                                                                       H       H         174-175                                    CH.sub.3                                                                            CH(CH.sub.3).sub.2                                                                       H       CH.sub.3  203-204                                    (CH.sub.2).sub.5                                                                           CH.sub.3                                                                              CH.sub.3      189-190.5                                  (CH.sub.2).sub.5                                                                           H       CH.sub.3    259-261                                      CH.sub.3                                                                            CH(CH.sub.3).sub.2                                                                       H       CH.sub.2 CCH                                                                            202-205                                    ______________________________________                                    

EXAMPLE 3

The postemergence herbicidal activity of the compounds of the inventionis demonstrated by the following tests, wherein a variety ofmonocotyledonous and dicotyledonous plants and a sedge species aretreated with test compounds dispersed in aqueous acetone mixtures. Inthe tests, seedling plants are grown in individual pots for about 2weeks, prior to being treated with respective compounds. The testcompounds are dispersed in 50/50 acetone/water mixtures containing 0.5%TWEEN® 20, a polyoxyethylene sorbitan monolaurate surfactant of AtlasChemical Industries, in sufficient quantity to provide the equivalent ofabout 0.28 kg to 11.2 kg per hectare of active compound when applied tothe plants through a spray nozzle operating at 40 psi for apredetermined time. After spraying, the plants are placed on greenhousebenches and are cared for in the usual manner, commensurate withconventional greenhouse practices. Two weeks after treatment, theseedling plants, with the exception of wild oats which are rated at 5weeks, are examined and rated according to the rating system providedbelow. The data obtained are reported in Table I below.

    ______________________________________                                                              % Difference                                                                  in Growth                                               Rating System:        from the Check*                                         ______________________________________                                        0-No effect           0                                                       1-Possible effect      1-10                                                   2-Slight effect       11-25                                                   3-Moderate effect     26-40                                                   5-Definite injury     41-60                                                   6-Herbicidal effect   61-75                                                   7-Good herbicidal effect                                                                            76-90                                                   8-Approaching complete kill                                                                         91-99                                                   9-Complete kill       100                                                     4-Abnormal growth, that is, a definite physiological                            malformation but with an over-all effect less than                            a 5 on the rating scale.                                                    ______________________________________                                         *Based on visual determination of stand, size, vigor, chlorosis, growth       malformation and over-all plant appearance.                              

Plant Abbreviations

Pn -- purple Nutsedge (Cyperus rotundus L.)

Se -- sesbania (Sesbania exaltata)

-- Mustard (Brassica kaber)

Pi -- pigweed (Amaranthus retroflexus)

Rw -- ragweed (Ambrosia artemisiifolia)

Mg -- morningglory (Ipomoea purpurea)

Ba -- barnyardgrass (Echinochloa crusgalli)

Cr -- crabgrass (Digitaria sanguinalis)

Fo -- green Foxtail (Setaria viridis)

Wo -- wild Oats (Avena fatus)

Tw -- teaweed (Sida sponosa)

Vl -- velvetleaf (Abutilon theophrasti)

Cn -- corn (Zea mays)

Co -- cotton (Gossypium hirsutum)

Sy -- soybean (Glycine max)

Ri -- rice (Oryza sativa)

    TABLE I      Postemergence Herbicidal Activity for Compounds having the Structure:      ##STR7##       Rate  Structure kg per Plant Species R.sub.1 R.sub.2 R.sub.3 R.sub.4     Hectare PN SE MU PI RW MG TW VL BA CR FO WO CN CO SY RI       CH.sub.3 CH(CH.sub.3).sub.2 H H 11.2 4 0 6 8 4 4 6 5 4 4 4 4 -- -- --     --     4.48 2 2 9 9 2 8 5 6 0 0 2 -- 4 9 9 7     1.12 2 0 9 9 0 7 0 2 0     0 0 0 0 8 8 0     0.56 0 0 9 8 0 7 0 0 0 0 0 0 0 7 7 0     0.28 0 0 9 8     0 4 0 0 0 0 0 0 0 4 4 0 CH.sub.3 CH(CH.sub.3).sub.2 CH.sub.3 CH.sub.3     11.2 1 0 8 8 0 4 1 4 0 0 0 0 -- -- -- --     4.48 5 3 9 9 0 6 2 2 0 0 2     -- 7 7 7 0     1.12 2 0 9 8 0 4 0 0 0 0 0 -- 6 7 4 0     0.56 0 0 9 8 0     4 0 0 0 0 0 -- 2 4 4 0 CH.sub.3 CH(CH.sub.3).sub.2 H CH.sub.2 CCH 11.2 0     0 8 3 0 0 5 4 0 0 0 0 -- -- -- --

EXAMPLE 4

The preemergence herbicidal activity of the compounds of the presentinvention is exemplified by the following tests in which the seeds of avariety of monocotyledonous, dicotyledonous and sedge plants areseparately mixed with potting soil and planted on top of approximately25 mm of soil in separate cups. After plants, the cups are sprayed withthe selected aqueous acetone solution containing test compound insufficient quantity to provide the equivalent of about 0.28 kg to 11.2kg per hectare of test compound per cup. The treated cups are thenplaced on greenhouse benches, watered and cared for in accordance withconventional greenhouse procedures. Two to 4 weeks after treatment, thetests are terminated and each cup is examined and rated according to therating system set forth above. The herbicidal proficiency of the activeingredients of the present invention is evident from the test resultswhich are reported in Table II below.

    TABLE II      Preemergence Herbicidal Activity for Compounds having the Structure:      ##STR8##       Rate  Structure kg per Plant Species R.sub.1 R.sub.2 R.sub.3 R.sub.4     Hectare PN SE MU PI RW MG TW VL BA CR FO WO CN CO SY RI       CH.sub.3 CH(CH.sub.3).sub.2 H H 11.2 9 1 8 8 0 8 8 7 7 6 7 4 -- --     ----     4.48 9 0 9 9 0 7 0 6 2 2 2 -- 2 7 7 1     1.12 7 0 8 8 0 7 0 2     1 1 1 -- 2 2 3 0     0.56 0 0 6 0 0 5 0 0 0 0 0 -- 0 -- 1 0 CH.sub.3     CH(CH.sub.3).sub.2 H CH.sub.3 11.2 6 0 8 9 0 4 0 2 0 0 0 0 -- -- ' --     CH.sub.3 CH(CH.sub.3).sub.2 CH.sub.3 CH.sub.3 11.2 9 7 9 9 0 8 6 8 0 1 5     1 -- -- -- --     4.48 9 8 9 9 0 7 1 7 2 0 1 -- 4 8 8 2     1.12 9 1 8 8     0 4 0 1 0 0 0 -- 4 8 7 0     0.56 8 0 7 6 0 4 0 0 0 0 0 -- 0 4 0 0     (CH.sub.2).sub.5 CH.sub.3 CH.sub.3 11.28 -- -- -- -- -- -- -- -- -- --     -- -- -- -- --    4.48 7 0 0 0 0 0 0 0 0 0 0 -- 0 -- -- 0    1.12 2 0 0     0 0 0 0 0 0 0 0 -- 0 0 0 0    0.56 0 0 0 0 0 0 0 0 0 0 0 -- 0 0 0 0     CH.sub.3 CH(CH.sub.3).sub.2 H CH.sub.2 CH 11.2 8 0 8 9 3 8 8 8 7 6 8 5     -- -- -- --     4.48 9 8 8 9 8 8 8 8 9 9 9 8 8 8 8 9     1.12 2 0 9 8 0     4 0 0 0 0 0 -- 6 7 4 0     0.56 0 0 9 8 0 4 0 0 0 0 0 -- 2 4 4 0     CH.sub.3 CH(CH.sub.3).sub.2 H CH.sub.2 CCH 11.2 0 0 8 3 0 0 5 4 0 0 0 0     -- -- -- --

I claim:
 1. A compound having the structure: ##STR9## wherein R₁ isalkyl C₁ -C₄ ; R₂ is alkyl C₁ -C₆, cycloalkyl C₃ -C₆, alkenyl C₂ -C₄,phenyl, halophenyl or benzyl, and when R₁ and R₂ are taken together withthe carbon to which they are attached they may form cycloalkyl C₃ 14 C₆optionally substituted with methyl; R₃ and R₄ each individuallyrepresent hydrogen, alkyl C₁ -C₄, alkenyl C₃ -C₅, alkynyl C₃ -C₅, orbenzyl; and the optical isomers thereof.
 2. A compound according toclaim 1, wherein R₁ is methyl; R₂ is alkyl C₁ -C₃, cyclohexyl or benzyl,or when R₁ and R₂ are taken together with the carbon to which they areattached they represent cyclohexyl; R₃ and R₄ each individuallyrepresent hydrogen, alkyl C₁ -C₃, allyl, dimethylallyl, propynyl orbenzyl; and the optical isomers thereof.
 3. A compound according toclaim 1,o-(5-iso-propyl-5-methyl-4-oxo-2-imidazolin-2-yl)-N,N-dimethylbenzamide.4. A compound according to claim 1,o-(5-iso-propyl-5-methyl-4-oxo-2-imidazolin-2-yl)-N-2-propynyl-benzamide.5. A compound according to claim 1,o-(5-iso-propyl-5-methyl-4-oxo-2-imidazolin-2-yl)-N-methylbenzamide. 6.A compound according to claim 1,o-(5-iso-propyl-5-methyl-4-oxo-2-imidazolin-2-yl)benzamide.
 7. Acompound according to claim 1,N,N-dimethyl-o-(4-oxo-1,3-diazospiro[4,5]dec-2-en-2-yl)benzamide.
 8. Acompound according to claim 1,N-methyl-o-(4-oxo-1,3-diazospiro[4,5]dec-2-en-2yl)benzamide.